A socketed pavise (the exceptional version of a tower shield)! I've made about 7 runs through the kurast bazaar in nightmare difficulty and seen about 10-20 pavises and tower shileds, but no socketed pavises. Unfortunately people don't realize how uncommon these are and don't pick them up to trade them nearly often enough. Also a rare pavise with an increased chance of blocking and a couple other modifiers that don't suck would be just as good. I give most of my stuff away, but I would do my best to reimburse you if you can find either of these. I would take a sigons shield off of somebody's hands too, but I'm not really all that excited about it. +1 skills isn't nearly as useful for a paladin with no passive skills to speak of as it is for the other classes. 74% chance to block for a paladin is not too shabby though.